Microfluidic devices in which liquids and the like are allowed to flow through microchannels having diameters of around several μm to several-hundred μm to effect biochemical reactions, to perform physicochemical separation manipulations, and the like have been known. In such a microfluidic device, a channel having a semicircular or circular cross section is needed. However, since a channel having a rectangular cross section has been often produced in a photolithography step widely used for producing a microfluidic device, a method for producing a channel having a semicircular or circular cross section has been proposed.
Patent Literature 1 describes a method for producing a microchannel device including a pair of half-divided bodies that have long plate shapes and include a groove formed on one face thereof and opened in a semicircular shape in one-end face, in which the half-divided bodies are joined.
Non Patent Literature 1 describes a method for producing a channel having a circular cross section. In this method, using a dispenser robot for automatically applying an adhesive or the like used when electronic equipment is produced, an ultraviolet-curable resin or the like is directly drawn in a channel pattern shape on a substrate to produce a mold. Then, channels having semicircular cross sections are produced by performing molding with PDMS (polydimethylsiloxane) using the produced mold. In addition, a channel for a circular cross section is produced by affixing the channels with semicircular cross sections to each other.
Non Patent Literature 2 describes a method for producing a circular PDMS microchannel which is suitable for visualization of micro-flow and simulates microvessels in vivo, such as confocus μPIV/PTV (Particle Image Velocimetry/Particle Tracking Velocimetry). In this method, a circular channel is formed by curing PDMS in a state in which a wire is embedded and then pulling the wire out.
Non Patent Literature 3 describes a method for configuring a microvascular network having a circular cross section from a polystyrene sheet. In this method, a semicircular master with silicon is configured in an electroplating step and embossed on polystyrene sheets, and the two obtained sheets are joined to form a channel having a circular cross section.